Recent neuroimaging studies suggest that the amygdala could be atrophied as early as the prodromal stage of Alzheimer‘s disease (AD ; e.g. Horinek, 2007). However, the level of atrophy in amygdalar volume and its behavioral consequences in patients remain largely unknown. This thesis will assess the relevance of assessing amygdalar activity for the early diagnosis of AD. Main goals will be to examine i) amygdalar volume loss and ii) amygdalar activity and behavioral correlates during emotional tasks in patients with mild cognitive impairment (MCI) and mild AD.
Protocols will be constructed in the theoretical framework of a promising hypothesis that considers the amygdala to be differentially involved in automatic and controlled emotional processing. This hypothesis is supported by recent data suggesting that automatic emotional relevance processing is selectively impaired, whereas compensatory mechanisms are engaged in explicit emotional categorization tasks.

Concerning the progressive atrophy of the amygdala in dementia,we will develop different protocols to unravel whether amygdalar changes constitute a promising biological marker of AD. The thesis will focus on links between emotional mechanisms and monitored attentional processes in AD. On one hand, some work shows that a decrease in emotional processing can be partially reduced when patients are invited to use an appropriate strategy, questioning the existence of a decline in monitored emotional processing in AD (Hot et al., 2013 ; Richard-Mornas et al., 2012). In order to test this assumption, fMRI study will be conducted to analyze the link between functional connectivity between amygdala and prefrontal cortex (Rosenbaum et al., 2010) and performance in monitored attention tasks involving emotional material. On the other hand, recent works suggest that cognitive difficulties in AD patients may be due to an uncertainty feeling regarding their capacities and may be modulated by a positive mood induction (Hot et al., 2014). To explore this issue, research will be conducted to assess the emotional induction on AD patients’ performances during monitored attention tasks. Studies will be performed in neuroscience approaches (EEG, MRI and Tdcs).